Happened to me twice while importing my wallet to different PC, as it turned out in my case, I got 1 word wrong. the moment I got all the 12 phrases right it displayed my correct balance and the correct wallet address.

Out of the 12 words I wrote down in order and kept, 1 of them, specifically the 9th didn’t register (or didn’t exist) so I had to choose another and it worked. But that led to 0 balance which is very confusing.

You need to write the words in order but maybe just like in my case you’ve written that “one letter” of that one word wrong. examples “aim” instead of “air” or “price” instead of “prize” or “oven” instead of “over” or maybe you forgot there is “d” in the end like “used” instead of “use”.